激光选区熔化GH3536高温合金成形特征与缺陷研究  

Forming Characteristics and Defects of GH3536 Superalloy by Selective Laser Melting

作　　者：李军[1] 刘婷婷[1] 廖文和[1] 韦辉亮 续金辉 尹清远 Li Jun;Liu Tingting;Liao Wenhe;Wei Huiliang;Xu Jinhui;Yin Qingyuan(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094

出　　处：《中国激光》2023年第12期204-213,共10页Chinese Journal of Lasers

基　　金：江苏省自然科学基金(BK20202007);中央高校基本科研业务费专项资金(30921011202)。

摘　　要：采用激光选区熔化成形GH3536高温合金可以实现复杂结构的高效率、高精度制造。但是,采用激光选区熔化制造GH3536高温合金零件面临成形质量影响因素多、工艺参数优化过程复杂等难题。本研究通过建立粉末尺度热流耦合模型探索了GH3536高温合金在不同激光选区熔化工艺参数下的成形特征,结合实验数据揭示了主要工艺参数对结构件成形质量的影响规律,阐明了成形过程中温度场、流场的复杂变化及其对成形缺陷的影响机制。在激光功率为190~250 W、扫描速度为0.94~1.25 m/s的典型工艺参数区间内,熔池中液态金属的最高流速可达5.45 m/s,冷却速率最大可达1.219×106K/s。若扫描间距过大,则粉末的熔化条件不足,沉积道接触位置出现部分未熔化粉末以及表面孔洞等缺陷。本研究结果为GH3536高温合金激光选区熔化过程特征的理解以及内部孔隙缺陷的控制提供了依据。Objective GH3536 superalloy is a typical difficult-to-machine material with high micro-strengthening phase hardness,severe work hardening,high shear stress resistance,and low thermal conductivity.When processing GH3536 superalloys using traditional methods,problems such as low-quality machined surfaces and serious tool breakages are often encountered.The preparation of GH3536 superalloy parts using selective laser melting(SLM)has become an important research topic.However,forming defects of the structural parts of SLM restrict the rapid manufacturing and application of nickel-based superalloys.Hence,research on the corresponding basic scientific issues is urgently required.This study focuses on the forming process of GH3536 superalloys;the printing process of an SLM GH3536 alloy is systematically studied by simulating the temperature and flow fields in the transient process and typical experiments.Heat transfer,liquid metal flow,the formation of inter-track pore defects,and temperature-time variations are explored,providing a basis for the optimization of the manufacturing process parameters and the improvement of the manufacturing quality.Methods Numerical simulation can comprehensively reveal the complex changes in the temperature and stress fields during the printing process and visualize multi-physics and molten pool s behavior and distribution characteristics under dynamic control conditions,and then support the prediction and real-time control of manufacturing defects.Our simulation can be summarized in the following steps.First,a heat and mass transfer model was established to simulate the SLM GH3536 superalloy printing process.Second,the temperature and flow fields of the molten pool during SLM were studied by changing the laser power,scanning speed,scanning distance,and number of printing layers.Finally,the GH3536 SLM experiment was carried out,and the deposition morphologies were characterized using an optical microscope.The simulation and experimental data deepened our understanding of the temperature

关 键 词：激光技术 增材制造 激光选区熔化 GH3536高温合金 模拟仿真 孔隙 

分 类 号：TG146[一般工业技术—材料科学与工程]